Cell wall, because of its ability to confer rigidity and shape, is one of the most important structural features of the procaryotic cells. Although the mechanism of biosynthesis of several complex saccharides has been well established in the past decade, the mechanism involved in the biosynthesis of cell wall polysaccharide and its incorporation into the peptidoglycan is not understood. The objective of this project is to investigate the stepwise biosynthesis of the peptidoglycan-polysaccharide complex in Streptococcus sanguis and other oral streptococci. It is hoped a common precursor could be identified and utilized for the control of these bacteria. Recently we have been able to incorporate the individual sugar components of cell wall polysaccharide into polyisoprenyl-phosphate lipid. Several unique features could be shared by the synthesis of wall teichoic acid as judged from the reports of other laboratories. In this proposal the following specific aspects will be investigated: 1. Further characterization of the monosaccharide-lipid. 2. The mechanism of biosynthesis and characterization of the lipid intermediates involved in the wall polysaccharide synthesis of S. sanguis and other oral bacteria. 3. Incorporation of the polysaccharide chain into peptidoglycans. 4. Inhibition of the wall biosynthesis by interfering with the utilization of the common precursors.